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Re: Noise with MKU24



You might try putting a fifty ohm resistor at the input and call what you
observe "normal".  Anything else would then not be normal.  Cliff K7RR

On Tue, 11 Dec 2001, Pieter Ibelings wrote:

> Hi,
> 
> I built a homebrew converter and it does exactly what you mentioned. I have
> verified that it is NOT oscillationg. I think it is caused by not having the
> correct load at the input. When there is nothing connected at the input, the
> noise is low. As soon as I connect a connector or a cable the noise goes up
> to normal levels. It almost seems like leaving the input totally open does
> not leave any noise resistance to generate noise at the input. This should
> be normal behavior. I wonder is someone has a better explanation.
> 
> Pieter
> N4IP
> 
> 
> 
> ----- Original Message -----
> From: "Reinhard Richter" <dj1km@dj1km.de>
> To: <gediminas@ameritech.ne>
> Cc: <amsat-bb@AMSAT.Org>
> Sent: Tuesday, December 11, 2001 6:32 AM
> Subject: [amsat-bb] Noise with MKU24
> 
> 
> >
> > ===8<==============Original message text===============
> > Hi,
> >
> > I need  help from somebody who has the same converter.
> > Are other converters doing the same thing ??????
> >
> > I have a MKU24 downconverter.
> > I set the gain when there is no antenna attached to show S1
> > noise level on the S meter.
> >
> > When I attach the unwired N type connector (new) to the converter's input
> > I'm reading an S4 noise level.
> >
> > Noise increases approximately by 3 S units just by attaching the bare N
> type
> > connector.
> >
> > Of course it works, I can hear stations , but I suspect I may be loosing a
> > few S units because of some kind of parasitic oscilation....
> >
> > I'm getting the same noise increase when I connect G3RUH patch feed to the
> > converter,
> > this I may be able to explain....the area is noisy, but I don't understand
> > why
> > I'm getting such a big noise increase just by attaching a bare N type
> > connector to the converter's input. And why is the noise increase the same
> > in both cases?
> >
> > Thanks,
> > Gedas (kc8ium)
> > -------------------------------------------------------
> > Hi Gedas,
> > I've read your inquiry and have asked Michael, DB6NT if something
> > is wrong with your converter. He replied that nothing is wrong. As long as
> > the insput does not see a correct load it will create that noise. It's
> juts
> > an incorrect impedance match. So don't worry.
> > 73
> > Reinhard (aka René)
> > DJ1KM
> >
> > ----
> > Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
> >
> ----
> Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
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> 

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